COLLABORATIVE RESEARCH: Biotic Diversity and Vertebrate Evolution in Late Devonian Non-Marine Ecosystems of North America

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AbstractCollaborative Research: Biotic diversity and vertebrate evolution inLate Devonian non-marine ecosystems of North AmericaNeil Shubin-EAR-0208377Edward Daeschler-EAR-0207721The Late Devonian (375-360 MYA) witnessed a burst of diversification of vertebrate life, including the origin of limbed vertebrates, and the elaboration of plants and invertebrates in terrestrial ecosystems. Accordingly, the description and analysis of Late Devonian vertebrates and ecosystems offers the ability to generate important data on the emergence of new taxa, new anatomical structures, new faunas, and new habitats during this critical moment of evolution. Our prior work (1993 to present) in the Late Devonian (Famennian Stage) Catskill Formation in Pennsylvania has produced well-preserved, highly diverse vertebrate assemblages from the same stratigraphic horizons as macrofossil plants, palynomorphs, arthropods, and bivalves. Exploratory work (1999-2000) in the Late Devonian (Frasnian Stage) Okse Bay Group in the Canadian Arctic has also revealed significantly fossiliferous units in this virtually unexplored region.This project will document and interpret the diversity of the non-marine parts of these Late Devonian systems in eastern North America. The temporal range will cover the Frasnian and Famennian Stages of the Late Devonian, a critical window in evolution. Fieldwork in the Famennian-age Catskill Formation has taken a significant step; the Pennsylvania Department of Transportation has given permission to remove a large wedge of overburden from the Red Hill locality, source of two early tetrapod taxa and a very diverse fauna and flora. Fieldwork in the Frasnian-age Okse Bay Group in the Canadian Arctic will focus on areas now recognized for their fossil productivity. The first major goal is the recovery, preparation and description of Late Devonian fossil material. Ensuing investigation of the phylogenetic affinities and stratigraphic position of fossil assemblages will allow both intraformational and global comparisons of biotic diversity. Assessment of intraformational stratigraphic relationships will enable an understanding of the biotic diversity in different portions of the fluvial systems. These analyses will inform: 1) higher level phylogenetic hypotheses of gnathostome vertebrates, 2) biostratigraphic and biogeographic analysis of the distribution of the Late Devonian tetrapods and fish, and 3) paleobiological investigation of the elaboration of terrestrial and freshwater ecosystems.